This invention is concerned with a backlash adjusting mechanism particularly for a bevel gear pair.
In many constructions of right angle sander/polishers, grinders and reciprocating saws, a bevel pair is utilized to convert the motion from the axis of rotation of the electric motor to an axis at a right angle for a sander/polisher and grinder, or for the scotch yoke mechanism of a reciprocating saw. In these applications utilizing such a bevel pair, the backlash therebetween must be carefully set so as to obtain the greatest strength and long life thereof.
There are many examples in the prior art of adjustments which may be made between bevel gears to obtain the proper backlash for optimum strength and life. In many of these prior art disclosures, considerable expense may be involved in the manufacture of parts necessary to achieve this backlash adjustment capability, or in the degree of care required in order to obtain the proper backlash. For example, the U.S. Pat. No. 2,996,929, discloses an arrangement utilizing a pair of mounting blocks, each supporting a bevel gear and shaft, which mounting blocks are slidably connected on one edge and connected by a lead screw on the other edge to vary the separation thereof for adjusting the backlash of the bevel gears. The U.S. Pat. No. 3,901,098 discloses an arrangement utilizing shims to provide for backlash adjustment, which requires an inventory of shims and a trail and error adjustment in order to achieve the proper backlash. The U.S. Pat. No. 4,311,063, discloses a sander/polisher having a combined sleeve and thrust bearing with an annular ramp that may engage a ramp surface on a bearing clamp. The combined sleeve and thrust bearing may be rotated so as to elevate a bevel gear, one of a bevel pair, into a proper backlash condition with a second of a bevel pair.
It will be recognized that implementation of the above noted bevel gear mesh adjusting mechanism would be expensive, either in terms of the components required or of the time consumed in obtaining a satisfactory mesh. What is required, is an arrangement in which the necessry gear mesh may be obtained in the environment of an assembly line, both expeditiously and accurately. Ideally, such an arrangement should be implemented as economically as possible.